JPH10245692A - Electroforming master mold using photolithography method and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to stably produce fine parts with high accuracy while checking the thickness of an electroforming member during the electroforming stage by providing a master mold with a pattern for monitor varying in the thickness of part of this mold and checking the degree of coverage of a monitor during the course of the electroforming stage. SOLUTION: The staircase-like monitor pattern 10 is formed by using a resist. The staircase-like monitor pattern 10 and a main pattern 11 are formed on a conductive base plate 40. The monitor and main patterns 10, 11 are nonconductive and the growth of the electroforming member 20 first starts from the surface of the substrate 40 having the electrical conductivity. The thickness of the electroforming member 20 increases and the electroforming part 20 grows so as to conceal the lowest part of the monitor pattern 10 as time passes by. Differences in the way of covering the monitor pattern 10 arises as the thickness of the electroforming member 20 changes. The differences in level of the monitor pattern 10 are finely set, by which the control of the thickness of the electroforming member 20 with the high accuracy is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an original die used for manufacturing by electroforming and a method for forming the same, and more particularly, to an original die using photolithography and a method for forming the same.

[0002]

2. Description of the Related Art Conventionally, a manufacturing method called an electroforming method has been widely used as a method for manufacturing fine parts.
This manufacturing method called an electroforming method is an electroforming liquid in which a conductive material is coated in advance on an original mold having the shape of a member to be formed, and the material formed by electroforming the original mold is mixed. Is a type of electrolytic plating method that forms an electroformed material on a conductive material by flowing an electric current between the electroforming solution and the conductive material coated on the surface of the original mold. .

[0003] Since the electroforming method can faithfully copy the shape of the original mold, if the original mold is formed finely and with high precision, then a large number of minute parts can be manufactured at once, making it possible to manufacture minute parts. Is a very effective method. However, as for the dimension in the growth direction of electroforming (the thickness of the electroformed member), the thickness is determined by the time required for the electroforming process, and so high precision cannot be expected.

Conventionally, the thickness of an electroformed member is estimated from the thickness of an electroformed member formed per unit time (hereinafter, this is referred to as a growth rate of an electroformed member) based on experience. The time required for the process was determined and controlled. However, the growth rate of an electroformed member varies greatly depending on many other factors, such as the temperature and composition of the electroforming solution or the magnitude of the current flowing during electroforming. Time has to be determined. As described above, it is extremely difficult to obtain a highly accurate thickness of an electroformed member, and for that purpose, experience of electroforming work has been most regarded as important.

[0005]

In the formation of parts by the conventional electroforming method, the thickness of the electroformed material formed cannot be confirmed during the manufacturing process. The thickness of the electroformed member formed per hour is predicted, and the thickness is controlled by the time for performing the electroforming. However, the thickness to be electroformed is not determined only by the time, but greatly depends on many other factors such as the temperature and composition of the electroforming solution, the magnitude of the current flowing during electroforming, and the like. Therefore, it is very difficult to accurately and constantly stably form a member formed by electroforming.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a pattern for monitoring (hereinafter referred to as a monitor pattern) having a different thickness is provided on a part of an original mold, and the pattern is formed during the electroforming process. But depending on how the monitor is covered,
The thickness of the electroformed member can be checked at a glance.

[0007] The monitor pattern is formed using a photolithography method. First, a thick photosensitive material (resist) is placed on a substrate coated with a conductive material.
Is divided into several times and is coated to a constant thickness every time. Each time coating is performed, exposure is performed so that a part of the substrate is patterned with a different pattern each time. After coating the resist several times, all of the laminated resists are exposed to the originally required shape, and finally, the previously exposed monitor pattern and the desired required pattern are simultaneously developed. Then, an original mold having several types of monitor patterns having different thicknesses and a pattern required for a desired electroformed shape is formed. If electroforming is performed using the original mold, as the electroforming proceeds, the monitor pattern is gradually covered, and the thickness of the electroformed member can be confirmed by the covering condition.

Further, in order to facilitate confirmation of the monitor pattern, the planar shape is changed according to the thickness of the monitor pattern. In particular, in order to make it easier to recognize, the thickness dimension of the monitor pattern is expressed in a planar shape.

[0009]

FIG. 1 is a diagram showing a method of forming an electroforming mold using a photolithography method according to the present invention.
First, a photosensitive resin material (hereinafter, referred to as a resist 12) is coated with an arbitrary thickness on a substrate 40 which itself has conductivity or has a surface coated with a material having conductivity. The coating method may be any method such as a coating method, a roller method, and a spin coating method. However, it is necessary to set the coating conditions in advance and grasp the thickness of the resist 12.

After the resist 12 is coated, using a first mask 31 having a desired pattern shape,
First exposure is performed (FIG. 1A). Since the pattern shape applied to the first mask 31 is not a pattern originally required as the original shape of the electroformed member, it may be merely arranged on a part of the substrate 40.

Although FIG. 1 shows a negative resist type in which the exposed portion remains after development, a positive resist type in which the exposed portion is developed does not hinder the present invention (however, the positive resist type does not hinder the present invention). When the resist type is used, the pattern of the mask is different from that of FIG.

Next, as shown in FIG. 1B, a new resist 12 is similarly coated on the first resist 12 already exposed to a desired pattern in the first exposure step. The second exposure is performed by the second mask 32 having a shape different from that used in the exposure step.

On the second mask 32 used in the second exposure step, a shape originally required as the shape of the electroformed member is drawn.

Finally, as shown in FIG. 1C, the first and second resist layers 12 are simultaneously developed to form a stepped monitor pattern 10 and a main pattern 11 to be used as an electroforming mold. Are formed.

FIG. 2 is a view showing an example of an electroforming master according to the present invention. In FIG. 2, a third exposure step is further added after the second exposure step described in FIG. 1, and development is performed thereafter. Therefore, the monitor pattern 10 formed on the substrate 40 is formed in three levels of thickness. The exposure of the pattern 11 is performed at the time of the third exposure step (final exposure step). By thus increasing the number of exposure steps, the level difference of the monitor pattern 11 can be arbitrarily increased.

FIG. 3 is a sectional view showing an electroforming process using the original mold of the present invention. A stepwise monitor pattern 10 and a main pattern 11 are formed on a conductive substrate 40 by the method shown in FIG. In FIG. 3, in order to explain the contents of the present invention more clearly, it is assumed that each step of the monitor pattern 10 is formed to have a thickness of 10 μm and three layers of 30 μm.

Monitor pattern 1 formed of resist
Since the pattern 0 and the pattern 11 are non-conductive, the growth of the electroformed member 20 starts first on the conductive substrate 40 (the state of step 1 in FIG. 3). Over time, the thickness of the electroformed member 20 increases, and the thickness of the electroformed member 20 becomes 10 μm.
When the distance exceeds m, the electroformed member 20 grows so as to cover the lowest part of the monitor pattern 10 (the state of the process 2 in FIG. 3).

If the electroforming time is further lengthened, as shown in the state of the step 3 in FIG. 3, the middle stage (the stage having a height of 20 μm) of the monitor pattern 10 is covered.

As described above, as the thickness of the electroformed member 20 changes, a difference occurs in how the monitor pattern 10 is covered. In step 1, the thickness of the electroformed member 20 is 0 to 10 μm, and in step 2, it is 10 to 10 μm. It can be confirmed on a plane that the thickness is 20 μm and the thickness in Step 3 is 20 to 30 μm.

In FIG. 3, each step of the monitor pattern 10 is set to 10 μm. However, by setting these steps finer, the thickness of the electroformed member 20 can be controlled with higher precision.

Further, as described above, in FIG. 3, the steps of the monitor pattern 10 are set to three steps. However, the number of steps is not limited to this, and the number of steps may be increased or decreased as necessary. It doesn't matter.

FIG. 4 is a sectional view of a monitor pattern having a step only in the vicinity of the thickness of the electroformed member to be controlled. The monitor pattern 10 as shown in FIG. 4 is formed by coating the resist thicker on the first layer and thinner on the second and third layers. The monitor pattern shown in FIG. 4 has a thickness of 200 μm and an accuracy of ± 5 μm, for example.
This is very effective when it is desired to control the thickness of the electroformed member, such as m, thickly and with high precision. In FIG. 4, the dimensions of each part are exaggerated for easy understanding of the description.

FIG. 5 is a diagram showing an example in which the display of the monitor pattern is made easy to understand. Although FIGS. 1 to 4 show the case where the monitor mask is formed in a step shape, it is not necessary to combine them into one pattern, and separate monitor patterns having different thicknesses may be prepared. Even in such a case, the method of forming the monitor pattern is basically the same as the method shown in FIG. 1, and only the mask needs to be changed.

In FIG. 5, the planar shape is changed according to the thickness of the monitor pattern 10 so that the monitor pattern can be easily viewed on a plane. In particular, in FIG. 5, the thickness dimension is displayed as a planar shape. By doing so, the thickness of the electroformed member is reduced by the monitor pattern 10.
As the thickness of the electroformed member exceeds the thickness of the electroformed member, the numerical value displayed on the monitor pattern 10 disappears.

[0025]

According to the present invention, a monitor pattern having several kinds of thicknesses in the growth direction of an electroformed member is provided by photolithography as a master for electroforming. As the electroforming proceeds, the thickness of the electroformed member gradually increases. When the thickness of the monitor pattern is exceeded, the monitor pattern is covered and becomes invisible.
As described above, the monitor patterns are provided in several thicknesses, and the monitor patterns are hidden one by one as the thickness of the electroformed member increases. By doing so, the thickness of the electroformed member can be confirmed even during the electroforming step, and the thickness can be easily controlled. Until now, experience has been regarded as important in managing the thickness, but according to the present invention, anyone can manage the thickness in the same manner.

Further, according to the present invention, by setting the difference in the thickness of the monitor pattern to a very small value, the electroforming can be performed with higher precision than when the thickness is controlled by the electroforming time as before. The thickness of the member can be controlled. Therefore, it is advantageous for forming a fine component.

[Brief description of the drawings]

FIG. 1 is a view showing a method of forming an electroforming mold using a photolithography method of the present invention.

FIG. 2 is a view showing an example of an electroforming master according to the present invention.

FIG. 3 is a cross-sectional view showing an electroforming process using the original mold of the present invention.

FIG. 4 is a cross-sectional view of a monitor pattern provided with a step only in the vicinity of the thickness of an electroformed member to be controlled using the present invention.

FIG. 5 is a diagram showing an example in which display of a monitor pattern is made easy to understand using the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 monitor pattern 11 main pattern 12 resist 20 electroformed member 31 first mask 32 second mask 40 substrate

Claims (3)

[Claims] 1. An electroforming mold in which a photosensitive resin is patterned on a substrate having a conductive surface, wherein a part of the mold has a pattern made of a photosensitive resin having a different thickness. An electroforming mold. 2. A method of forming a mold for electroforming in which a photosensitive resin is patterned on a substrate having a conductive surface, wherein the substrate is coated with the photosensitive resin and exposed to a desired pattern. A first exposure step, and a second step of coating the photosensitive resin exposed to a desired pattern in the first exposure step with a photosensitive resin and exposing the photosensitive resin to a pattern different from the first exposure step. A method for forming an electroforming mold, comprising: an exposure step; and finally, a step of developing the photosensitive resin and patterning the photosensitive resin. 3. The electroforming mold according to claim 1, wherein the pattern has a pattern in which a thickness dimension is indicated by a planar shape.